The value of energy spectral CT in the differential diagnosis between benign and malignant tumor of the musculoskeletal system / 实用放射学杂志

ABSTRACT

Objective To explore the value of spectral curve in the differential diagnosis of benign and malignant tumor of the musculoskeletal system.Methods 100 patients with mass of the musculoskeletal system which were found by MRI underwent Dis-covery HD750 Gemstone CT scan ,and the images acquired were processed.Areas with homogenous density which did not contain necrosis,cyst,hemorrhage and calcification were chosen as region of interest(ROI).The optimal Kev on single energy images was selected,then the Kev-CT curve was automatically generated.All 100 patients proved by histological examination were divided into four groups,38 cases were as group A with benign tumor,10 cases as group B with borderline tumor,49 cases as group C with ma-lignant tumor and 3 cases of lipoma(that were analyzed separately since its curve was arc shaped).Average slope rate of every group was calculated according to the formulaK=(HU40keV-HU80keV)/40.Kruskal Wallis test was applied for statistical analysis,P value of less than 0.05 was considered statistical significant.Results The spectral curve of group C was sharply falling type with a mean slope rate of 1.64±1.00,that of group A was gradually falling type with a mean slope rate of 0.75±0.30,and that of group B was 1.34±0.45.The difference of slope rate between group A and C and between A and B were of statistical significance(P<0.05).The spectral curve of 3 lipomas showed arc shaped rising type with a mean slope rate of-2.00.Conclusion Spectral curve is useful in the differential diagnosis of benign and malignant tumor of the musculoskeletal system.Arc shaped curve is a specific sign for tumors containing abundant fat.